Neurochemical correlates of muricidal behavior in rats.

Surgical, pharmacological or environmental manipulation are widely employed to induce muricidal behavior in naive laboratory male rats. The genetic predisposition of an animal strain to kill mice remains, however, an important factor to obtain the muricidal reaction. Data from the pertinent literature suggest that muricidal behavior may possibly be sustained by increased dopaminergic or catecholaminergic activity in the presence of reduced serotoninergic activity. The results here presented indicate, instead, that complete abolition of brain serotoninergic control, i.e., maximal depletion of brain serotonin, is just enough per se to induce muricidal activity. Further, this chemically-induced muricidal activity goes well beyond any pre-existing strain predisposition to kill mice or not.